Message-ID: <2000050208250568199@zetnet.co.uk>
Date: Tue, 2 May 2000 08:25:05 +0100
To: rsgb_lf_group@blacksheep.org
From: "Peter Dodd" <g3ldo@zetnet.co.uk>
Subject: LF: Re: Telsa Coils
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Yesterday, Monday, I operated from GB2CPM, not on LF but at the HF 
permanent amateur station that forms part of the radio section of the museum. 
At the Electricity Hall a group of Telso Coil builders had converged 
for a Telsa coil session. This comprised two groups, an indoor 
exibition using small coils ranging from 10cm long to 1m long; and 
the second group with the big coils (up to 2m long) which had to be 
done outside because of the very high voltages they produced.
The indoor goup had the advantage having a large room that could be 
darkened allowing the spectacular display to bee seen to its best 
advantage. The room had to be ventilated between sessions to clear 
out all the ozone!
The outdoor group set up a test area in the afternoon, starting by 
digging a cruciform shaped trench and laying down a lot of copper 
tubing and soaking it in brine before filling it in. The components 
of three large coils arrived in special vans and I was able to watch 
and photograph these coils and the electrical control and power 
systems being assembled.

The length of the main coils of the larger Telsa machines ranged from 
1 to 2m with a length/diameter ratio of around 3:1. The inductance of 
the main coils ranged from 400mH to 1.2H depending on the size of the 
machine. All coils seemed to be close wound with 1mm enamelled copper 
wire. The primary coils were made of 10mm copper tubing with clip 
connections for 'tuning'.

This main set of experiments had to be done after the museum had 
closed to the public and when it was getting dark. The corona 
discharge from 1meV machine was truely spectacular and  made our hair 
stand on end!

I was much taken with the technology of these machines, particularly 
the care with which the coils had been wound and the construction of 
high capacity high voltage capacitors. Some members of the group were 
interested in our activities in a similar technology.

If you want to know more about the Telsa Builders activities see 
<www.tcbouk.org.uk>

-- 
Regards, Peter, G3LDO

<g3ldo@zetnet.co.uk>